Certain devices, such as credit card or debit card reading devices, include circuitry that reads, stores, or transmits sensitive information. Sensitive information can include credit card numbers, debit card numbers, personal identification number (“PIN”) codes, or personal identification information, for example. If unprotected, a malicious party can sometimes retrieve such sensitive information from the devices by accessing the circuitry that stores or transmits the sensitive information.
Some devices that read, store, or transmit sensitive information include a tamper circuit that passes current through a tamper trace. Such a tamper circuit can detect tampering by detecting when current stops flowing along the conductive tamper trace. Such a tamper circuit can sometimes be bypassed if a malicious party short-circuits the tamper circuit, breaks or reroutes a tamper trace by drilling into the device, or floods a portion of the tamper circuit with conductive ink, among other attacks.
Thus, there is a need in the art for improved tamper circuitry.